The present invention relates to a load introducing element for a control surface of an aircraft or a spacecraft, as well as to a method for manufacturing the same, and to an aircraft including the same.
Larger control surfaces of commercial passenger airplanes often include ribs, which are mounted on at least one spar and are enveloped by an outer skin. Control surfaces with a relatively complex movement pattern (which, for example, goes well beyond a simple flapping) require a special mounting and special drive elements. Thus, for example, in order to increase the lift coefficient in certain flight phases Fowler flaps move in both a translatory and rotational manner and, correspondingly, are mounted in a moveable manner (for example, on pendulum supports, roller carriages or the like) and deflected by a pivotably mounted actuator.
Therefore, a control surface design which is adapted to the above features includes at least one rib that serves as the interface between loads that occur on the control surface and the structure of the craft. Furthermore, this rib can be used to mount the control surface. Currently such “load introducing ribs” are manufactured as a metal part to be milled—even in the case of a total CRP [carbon fiber reinforced plastic] construction of the control surface itself—and are mechanically connected to the control surface (for example, by interlocking connecting elements).
The production of such a metal load introducing rib is very expensive because it involves mechanical machining of a solid workpiece and, thus, results in high costs. Furthermore, there is the drawback that in the case of control surfaces that are made of fiber reinforced composite materials, a metal load introducing rib has a different heat expansion behavior than the control surface, attached to it. The result may be mechanical stresses that can be compensated only by means of suitably designed structures or by flexible mountings. Consequently such metal load introducing ribs are extremely disadvantageous in modern commercial passenger airplanes with control surfaces that are made of fiber reinforced composite materials.